Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753874AbaFDPGi (ORCPT ); Wed, 4 Jun 2014 11:06:38 -0400 Received: from mail-wi0-f171.google.com ([209.85.212.171]:41037 "EHLO mail-wi0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752316AbaFDPGe convert rfc822-to-8bit (ORCPT ); Wed, 4 Jun 2014 11:06:34 -0400 MIME-Version: 1.0 In-Reply-To: <20140604144639.GI28484@ulmo> References: <20140604144639.GI28484@ulmo> From: =?UTF-8?Q?Rapha=C3=ABl_Poggi?= Date: Wed, 4 Jun 2014 17:05:49 +0200 Message-ID: Subject: Re: pwm: atmel: problem when disable pwm To: Thierry Reding , linux-kernel@vger.kernel.org, inux-pwm@vger.kernel.org Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Thanks for your answer. I'm seeing the problem with the version 3.10-at91. I tried with the newer version of the driver which add the 916030db4399 commit and I have the same bug. 2014-06-04 16:46 GMT+02:00 Thierry Reding : > Adding in the linux-pwm mailing list. > > On Wed, Jun 04, 2014 at 02:56:13PM +0200, Raphaël Poggi wrote: >> Hello, >> >> I'm using the pwm-atmel driver to control led, but i'm facing a problem. >> >> When writing "echo 0 > /sys/class/leds/d1/brightness" (to switch off >> the led) sometimes the led stayed active. >> >> After investigation I think this problem is due to this function: >> >> static void atmel_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm) >> { >> struct atmel_pwm_chip *atmel_pwm = to_atmel_pwm_chip(chip); >> >> atmel_pwm_writel(atmel_pwm, PWM_DIS, 1 << pwm->hwpwm); >> >> clk_disable(atmel_pwm->clk); >> } >> >> By disable the pwm channel, I think the duty cycle "0" has not been >> update, and the channel is disable and stayed in active state (high or >> low depending of polarity). > > This sounds like a bug that could be fixed by this commit: > > 916030db4399 pwm: atmel: correct CDTY calculation > > What version of the kernel are you seeing this problem with? The above > commit was first added in v3.15-rc1, so maybe try that or any later > version to see if that fixes it. > > Thierry -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/